NEMA Standards Publication ICS 61800-6 TR-2015
Adjustable Speed Electrical Power Drive Systems
Part 6: Guide for Determination of Types of Load Duty
and Corresponding Current Ratings
Published by:
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© 2015 National Electrical Manufacturers Association
NEMA ICS 61800-6 TR-2015
Page i
Foreword
1) The IEC (International Electrotechnical Commission) is a worldwide organization for
standardization comprising all national electrotechnical committees (IEC National Committees).
The object of the IEC is to promote international co-operation on all questions concerning
standardization in the electrical and electronic fields. To this end and in addition to other activities,
the IEC publishes International Standards. Their preparation is entrusted to technical committees;
any IEC National Committee interested in the subject dealt with may participate in this preparatory
work. International, governmental and non-governmental organizations liaising with the IEC also
participate in this preparation. The IEC collaborates closely with the International Organization for
Standardization (ISO) in accordance with conditions determined by agreement between the two
organizations.
2) The formal decisions or agreements of the IEC on technical matters express, as nearly as
possible, an international consensus of opinion on the relevant subjects since each technical
committee has representation from all interested National Committees.
3) The documents produced have the form of recommendations for international use and are
published in the form of standards, technical specifications, technical reports or guides and they
are accepted by the National Committees in that sense.
4) In order to promote international unification, IEC National Committees undertake to apply IEC
International Standards transparently to the maximum extent possible in their national and regional
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5) The IEC provides no marking procedure to indicate its approval and cannot be rendered
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6) Attention is drawn to the possibility that some of the elements of this technical report may be the
subject of patent rights. The IEC shall not be held responsible for identifying any or all such patent
rights.
The main task of IEC technical committees is to prepare International Standards. However, a technical
committee may propose the publication of a technical report when it has collected data of a different
kind from that which is normally published as an International Standard, for example “state of the art”.
IEC 61800-6, which is a technical report, has been prepared by subcommittee 22G: Semiconductor
power converters for adjustable speed electric drive systems, of IEC technical committee 22: Power
electronics systems and equipment.
This first edition cancels and replaces IEC 61136-1, issued in 1992, and constitutes a technical
revision.
The text of this technical report is based on the following documents:
Enquiry draft
Report on voting
22G/85/DTR
22G/100/RVC
Full information on the voting for the approval of this technical report can be found in the report on
voting indicated in the above table.
This publication has been drafted in accordance with the ISO/IEC Directives, Part 2.
The committee has decided that the contents of this publication will remain unchanged until 2008. At
this date, the publication will be
•
•
•
•
reconfirmed;
withdrawn;
replaced by a revised edition, or
amended.
© 2015 National Electrical Manufacturers Association
NEMA ICS 61800-6 TR-2015
Page ii
Contents
Foreword .................................................................................................................................................. i
1
2
3
Scope and Object.............................................................................................................................. 1
1.1
DV (US DEVIATION) .............................................................................................................. 1
1.2
NORMATIVE REFERENCES ................................................................................................. 1
1.3
DV ........................................................................................................................................... 1
Terms, Definitions, and Symbols ...................................................................................................... 1
2.1
TERMS AND DEFINITIONS ................................................................................................... 1
2.2
SYMBOLS............................................................................................................................... 5
Rated Values ..................................................................................................................................... 6
3.1
GENERAL ............................................................................................................................... 6
3.2
SYSTEM OF ESTABLISHING RATED CURRENT-TIME VALUES FOR
SEMICONDUCTOR ASSEMBLIES AND EQUIPMENTS ...................................................... 7
3.3
3.4
4
3.2.1
General ...................................................................................................................... 7
3.2.2
Rated Current of a Common Converter Transformer ............................................... 7
3.2.3
Rated Values of a Double Converter ......................................................................... 7
3.2.4
Determination of Type of Load Duty .......................................................................... 7
RATED CURRENTS FOR EQUIPMENTS AND SECTIONS ................................................. 7
3.3.1
General ...................................................................................................................... 7
3.3.2
Rated Currents for Uniform Load Duty ...................................................................... 8
3.3.3
Rated Currents for Intermittent Peak Load Duty ....................................................... 8
3.3.4
Rated Currents for Intermittent Load Duty ................................................................ 8
3.3.5
Rated Currents for Intermittent Load Duty with No-Load Intervals ............................ 8
3.3.6
Rated Currents for Repetitive Load Duty................................................................... 8
3.3.7
Rated Currents for Non-Repetitive Load Duty ........................................................... 9
OVERLOAD AND SURGE CURRENT CAPABILITY ........................................................... 11
Duty Classes for Non-Repetitive Load Duty .................................................................................... 11
Figures
Figure 1 Typical Current-Time Chart for Uniform Load Duty ................................................................... 2
Figure 2 Typical Current-Time Chart for Intermittent Peak Load Duty ..................................................... 2
Figure 3 Typical Current-Time Chart for Intermittent Load Duty .............................................................. 3
Figure 4 Typical Time Chart for Intermittent Load Duty with No-Load Intervals ...................................... 3
Figure 5 Example of Current-Time Chart for Repetitive Load Duty ......................................................... 4
Figure 6 Typical Current-Time Chart for Non-Repetitive Load Duty ........................................................ 4
Figure 7 Equivalent Repetitive Load Duty Load-Time Chart .................................................................... 9
Figure 8 Typical Rating Curves for Non-Repetitive Load Duty............................................................... 10
Tables
Table 1 List of Symbols ............................................................................................................................ 5
Table 2 Duty Classes for Non-Repetitive Industrial Applications ........................................................... 11
© 2015 National Electrical Manufacturers Association
NEMA ICS 61800-6 TR-2015
Page 1
1
Scope and Object
This technical report provides alternative methods for specifying ratings for adjustable speed electrical
power drive systems (PDS) and, in particular, their basic drive modules (BDM).
It is not intended to cover adjustable speed drives for traction purposes.
General rules for rating specification for low voltage adjustable speed d.c. power drive systems are
contained in IEC 61800-1, and for low voltage adjustable frequency a.c. power drive systems in IEC
61800-2.
© 2015 National Electrical Manufacturers Association